US Patent 9962228 Length conservative surgical instrument

A surgical instrument is described that includes a surgical effector moving with N degrees of freedom for manipulation of objects at a surgical site during surgical procedures. The N degrees of freedom are manipulated by N+1 input controllers and a plurality of cables, the controllers and cables coupled to the surgical effector and configured to change the orientation of the surgical effector about the N degrees of freedom when actuated. In some embodiments, the N+1 input controllers and plurality of cables are further coupled to a pantograph, the pantograph configured to move in a reciprocal manner to the surgical effector when the input controllers and cables are actuated.